William Howard Taft

“ The government under section 10, in a case of false imprisonment, stands exactly as if it were a railway corporation operating as a common carrier. Such a corporation would clearly be responsible for an arrest of the kind here shown, if without probable cause and made by one of its detectives employed to protect the property intrusted to its care as a common carrier. ”

“ The action for false imprisonment is in the nature of a trespass for a wrong or illegal act in which the defendant must have personally participated directly or by indirect procurement. The gist of it is an unlawful detention, and, that being shown, the burden is on the defendant to establish probable cause for the arrest. The want of probable cause, certainly in the absence of proof of guilt or conviction of the plaintiff, is measured by the state of the defendant's knowledge, not by his intent. It means the absence of probable cause known to the defendant when he instituted the suit. ”

“ But the standard applied to defendant's consciousness is external to it. The question is not whether he thought the facts to constitute probable cause, but whether the court thinks they did. Holmes on the Common Law, 140. Probable cause is a mixed question of law and fact. ”